Accurate and efficient flow metering as to the volume of fluid (e.g., liquid, gas or supercritical fluid) is of widespread industrial concern. Chemical processing requires elaborate, continuous and timely monitoring of fluids passing through lines to reactors or to shipment. Industry is best served by a unitary meter that has a capacity to monitor flow rates from the lowest to the highest anticipated flow demands. Realizing this end has been hampered by the finite flow rate limitations of each of the various meter types now in use. Diaphragm meters are accurate at flow rates from about 0 to about 10.sup.4 cfh, but generally capacity limited as to substantially greater flows. Clearly the maximum flow rate for a diaphragm meter may be well below industrial demands for a particular system. Turbine meters, on the other hand, have considrably higher capacities, but have inherent limited flow measurement capability. Other types of flow meters are well known to those skilled in the art.
The instant invention provides a unitary meter providing for accurate extended range metering over an extended range of flows that previously could not be metered by a unitary device. Also disclosed is a novel process of accomplishing such extended range metering.